<template>
  <div>
    <div class="goods">
    <div class="menu-wrapper">
      <ul>
        <li class="menu-item" v-for="(good, index) in goods"
            :key="index" :class="{current: currentIndex===index}" @click="clickMenu(index)">
          <img class="icon" :src="good.icon" v-if="good.icon">
          <span class="text bottom-border-1px">{{good.name}}</span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper">
      <ul ref="foodsUl">
        <li class="food-list-hook"
            v-for="(good,index) in goods"
            :key="index"
        >
          <h1 class="title">{{good.name}}</h1>
          <ul>
            <li class="food-item border-1px"
                v-for="food in good.foods"
                @click="showFood(food)"
            >
              <div class="icon">
                <img width="57" height="57"
                     :src="food.icon">
              </div>
              <div class="content">
                <h2 class="name">{{food.name}}</h2>
                <p class="desc">{{food.description}}</p>
                <div class="extra">
                  <span class="count">月售{{food.sellCount}}份</span>
                  <span>好评率{{food.rating}}%</span>
                </div>
                <div class="price">
                  <span class="now">￥{{food.price}}</span>
                  <span class="old" v-show="food.oldPrice">￥{{food.oldPrice}}</span>
                </div>
                <div class="cartcontrol-wrapper">
                  <cart-control :food="food"></cart-control>
                </div>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>
    <shop-cart></shop-cart>
  </div>
    <food :food="food" ref="food"></food>
  </div>
</template>

<script>
  import { mapState } from 'vuex'
  import BScroll from 'better-scroll'
  import CartControl from 'components/CartControl/CartControl'
  import Food from 'components/Food/Food'
  import ShopCart from 'components/ShopCart/ShopCart'

  export default {
    data () {
      return {
        scrollY: 0, //右侧Y轴滑动的坐标
        tops: [], // 包含右侧所有分类小列表的top值
        food: {}
      }
    },
    components: {
      CartControl,
      Food,
      ShopCart
    },
    computed: {
    ...mapState(['goods']),
        currentIndex() {
        const {scrollY, tops} = this;
        //根据条件计算产生一个结果
        return tops.findIndex((top,index)=>{
          return scrollY >= top && scrollY < tops[index+1]
        });
      }
    },
    mounted() {
      this.$store.dispatch('getShopGoods', ()=>{// goods更新了, 界面还没有更新
        this.$nextTick(()=>{
          this._initScroll();
          this._initTops();
        })
      })
    },
    methods: {
      //初始化scroll
      _initScroll () {
        new BScroll('.menu-wrapper',{
          click: true
        });
        this.foodsScroll = new BScroll('.foods-wrapper',{
          probeType: 2,  //惯性滑动不会触发
          click: true
        });
        //给右侧列表绑定scroll监听
        this.foodsScroll.on('scroll',({x,y})=>{
          this.scrollY = Math.abs(y);
        });
        this.foodsScroll.on('scrollEnd',({x,y})=>{
          this.scrollY = Math.abs(y);
        });
      },

      _initTops () {
        //1.初始化tops
        const tops = [];
        let top = 0;
        tops.push(top);
        //2.收集所有分类的li
        const lis = this.$refs.foodsUl.getElementsByClassName('food-list-hook');
        Array.prototype.slice.call(lis).forEach((li)=>{  //将lis对象转换成一个Array对象
          top += li.clientHeight;
          tops.push(top);
        });
        //3.更新数据
        this.tops = tops;
      },

      clickMenu(index) {
        //使用右侧列表滑动到相应的位置
        this.scrollY  = this.tops[index];
        this.foodsScroll.scrollTo(0,-this.tops[index],300)
      },

      showFood(food) {
        this.food = food;
        this.$refs.food.toggleShow();
      }
    }
  }
</script>

<style lang="stylus" rel="stylesheet/stylus">
  @import "../../../common/stylus/mixins.styl"

  .goods
    display: flex
    position: absolute
    top: 245px
    bottom: 46px
    width: 100%
    background: #fff;
    overflow: hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px
      background: #f3f5f7
      .menu-item
        display: table
        height: 54px
        width: 56px
        padding: 0 12px
        line-height: 14px
        &.current
          position: relative
          z-index: 10
          margin-top: -1px
          background: #fff
          color: $green
          font-weight: 700
          .text
            border-none()
        .icon
          display: inline-block
          vertical-align: top
          margin-top 20px
          width: 12px
          height: 12px
          margin-right: 2px
          background-size: 12px 12px
          background-repeat: no-repeat
        .text
          display: table-cell
          width: 56px
          vertical-align: middle
          bottom-border-1px(rgba(7, 17, 27, 0.1))
          font-size: 12px
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        font-size: 12px
        color: rgb(147, 153, 159)
        background: #f3f5f7
      .food-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        bottom-border-1px(rgba(7, 17, 27, 0.1))
        &:last-child
          border-none()
          margin-bottom: 0
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          .name
            margin: 2px 0 8px 0
            height: 14px
            line-height: 14px
            font-size: 14px
            color: rgb(7, 17, 27)
          .desc, .extra
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
          .desc
            line-height: 12px
            margin-bottom: 8px
          .extra
            .count
              margin-right: 12px
          .price
            font-weight: 700
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240, 20, 20)
            .old
              text-decoration: line-through
              font-size: 10px
              color: rgb(147, 153, 159)
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: 12px
</style>
